Truck tonneau cover assemblies have previously been utilized to open and close truck beds at the upper extremities of lateral side walls, a front wall, and a rear tailgate that cooperatively define the truck bed. Such cover assemblies enclose cargo being carried and also enclose the truck bed from the environment even when the truck bed is empty.
Truck tonneau cover assemblies have previously included covers that are unrolled for use to close the associated truck bed and rolled for storage when the truck bed is to be opened. See U.S. Pat. No. 3,086,811 Hartviksen; U.S. Pat. No. 3,146,824 Veilleau; U.S. Pat. No. 4,252,362 Campbell; and U.S. Pat. No. 4,611,844 Romano. Another truck tonneau cover assembly disclosed by the U.S. Pat. No. 4,479,677 of Gullette et al. has a cover that is wound and unwound for storage and use and is also provided with curved slats that are positioned below the unrolled cover in order to provide an upwardly curved shape for shedding water. At its lateral edges, the cover has snaps which are secured to provide sealing of the cover over the truck bed. A further truck tonneau cover assembly of the rollable type is disclosed by the U.S. Pat. No. 2,594,910 of Germann and includes tracks that converge toward each other and receive opposite edges of the cover which has slats with opposite ends also received by the tracks. Converging portions of the track curve the ribs and the cover upwardly to shed water. There is no seal provided between the lateral edges of the cover and the track such that rainwater or other moisture is not prevented from entering the truck bed with the cover closed.